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WARLOCK!!!!!! You are alive! To be honest, no. I am currently testing two different and simpler suspension calculations to see which if either works best. The one on this thread is ok. It can give ok results as a starting point, but I have found that it isn't worth the effort to use. In my opinion (not fact) i think there are better ways to set your suspension.

Lol, you and me both, brother!! I feel like Tom Cruise at the beginning of Days of Thunder!!

To give everyone an example, I tested a LaFerrari. One method of tuning the springs I used Total Weight/Number of Axles, took that number and multiplied that by the weight distribution. So for one build the math looked like this: 3005/2 = 1502.5, then 1502.5 x .43 = 646.075 or 646 for the front and 1502.5 x .57 = 856.425 or 856 for the rear. I ran a number of laps using that formula then input Rabbits formula and ran a bunch more laps. Both setups gave me virtually the same time give or take .100. So in my limited opinion, I don't feel his method is worth the pain of having to know his complicated formula. I have tested his formula on a number of cars and no matter what, I pretty much get similar results. Take this info for what it's worth.

Oh and the formula is as follows: Total Weight/2 = Y, Y x Front Weight Distribution = Front Spring Rate Y x Rear Weight Distribution = Rear Spring Rate..... So for example a car weighing 2500 lbs with a Front Weight Distribution of 45% would look like this ---> 2500 x .5 (or 2500/2) = 1250 --> 1250 x .45 = 562.5 front and 1250 x .55 = 687.5 rear.

Yeah bro im ALIVE!!!! getting back in the game....now thats more like it.

Or more less Woody Allen in "white man can't jump"....lol...dumb as heck....

Edited by user Monday, October 26, 2015 12:50:00 PM(UTC)  | Reason: Not specified

One last thing. Rabbit, unless I missed something, your math in your example is wrong. You put 4 x PI squared x 2.5 squared x square root (284)x 1.45 squared =4839.9. The math when I did it looks like this: 4 x PI squared (9.86) x 2.5 squared (6.25) x ((square root of 284 (16.85) x 1.45 squared (2.4)) = 4 x 9.86 x 6.25 x (16.85 x 2.4) = 4 x 9.86 x 6.25 x 40.44 = 9968.46. Which brings me to my final point, I have tested your numbers using different combinations of frequencies and travel and often times you get numbers that give spring rates that aren't even possible, such as a front spring rate of 1400.

Then you're getting something wrong. If you're getting those numbers look at what is going on as I'm getting a range of 200-700. I also stated above my example was wrong in a reply to someone else.

The formula should look like this
4xPI squared x 2.5 squared x square root 284 (mass per corner in KG not LBs) x 1.45 squared =8742.485......
Therefore Spring rate = 874.25 (or as close as you can get)
Set it up for weight distribution +/- difference of distribution so for a 52/48 bias your numbers would look like this.

864.195 (864.2)
830.256 (830.26)

Not 4xPI squared x 2.5 squared x (square root 284 X 1.45 squared). The brackets will force the end of the calculation to be calculated first giving you the wrong total.

Like I said above aswell I'm not forcing anyone to use it, I'm just sharing some knowledge. Before you try and separate your tuning from mine you should try one of the cars set up using my methods and maths. It's all well and good setting the springs up and testing it against your set up but mine is based entirely around around my springs.

A good example of what can be achieved with it is the Ferrari 250berlinetta lusso

I'll be the first to admit when I'm wrong, but take the Laferrari for example with a weight of 3005lbs. PI squared is 9.86. It's a high downforce car so we will pick a middle frequency of 4. 4 squared is 16. and 3005/4 = 751. 751lbs = 340kg. The square root of 340 is 18.44. 1.45 squared is 2.1. So here's the math 4 * 9.86 * 16 * 18.44 * 2.1 = 24,436.39 or 2,443.6. 2443.6 is not a valid spring rate.

The only way to get your math to work out on a LaFerrari is to choose a low frequency like one from a medium downforce car, so 2.5 AND choose a low travel rate of 1.25. So then the math would be 4 * 9.86 * 6.25 * 18.46 * 1.56 = 7098.6 or 709.8. There is a valid spring rate. BUT, the LaFerrari is a high downforce car, not a medium and it renders any travel choice useless. So to make your calculations work, you are locked in to certain numbers which take your options away. Again, that's a problem. I'm not telling you that what youre doing is **** , I'm just trying to provide you with feedback in the area of application in the game.

Ok in that instance that doesn't work out right... ****

Thanks for pointing that out, will get on it and look into it.


Update:
Right I've looked into it and believe I fixed it, would you like to just confirm it??? Random??

So the version that works right now is 4 x PI squared x Frequency x square root (weight per corner in KG not LBS) x travel squared.

Edited by user Tuesday, October 27, 2015 4:46:12 AM(UTC)  | Reason: Not specified

Also while the la Ferrari and such maybe high downforce they class as sports cars and therefore medium. When I said high downforce I meant solely race cars.

Ok. A friendly suggestion might be to possibly give a better classification for frequency so that guys know where their car fits in exactly. Also I would recommend giving parameters for suspension travel besides trucks.

Also, I will try it out again. I think something that would help guys out more when using this suspension calculation is an explanation of how you do your rebound/bump and ARBs because they tie so closely in with springs.

That is what gets me a little lost. I sorta understand the math...sorta, lol. But when it gets to rebound, bump and the effect of adjustments to the arb's. Mmmmm Arby's haha.... Anyway, those adjustments are where I think I aM messing up. Sorry, little slow.

Will re write the top post tonight explaining things better so it's al together, in the mean time here's 2 examples. 1st one is a set up on a soft Spring rate, second is a hard Spring rate.

Soft set up (Ferrari 250 Berlinetta Lusso)
ARBs
12.16
9.41
Springs and ride height
249.6
239.5
8.1
7.9
Damping
6.5
6.8
6.8
6.3

Hard set up (Toyota Supra)
ARBs
26.52
18.16
Spring and ride height
572.9
713.4
6.0
5.8
Damping
8.3
7.9
5.6
4.9

See how with the softer set up I set the ARBs softer to allow the body to roll loading the tyres?? I've also got a higher bump stiffness to control the pitch and drive, allowing me to set the rebound lower to smooth the ride. So the damping is controlling the ride over all stability, ARBs are controlling tyre loading and springs are allowing more movement to give more grip using all 3 springs efficiently. You'll need to run more camber at the front with a lower caster to rule out excessive camber while turning.

The hard Set up we see the opposite effect. I've got a much bigger ratio between bump and rebound. If you boost the rebound on stiff springs you'll be skating over the track instead of griping to it, so we reduce the bump, increase the rebound to give a more complaint set up. What we also do it because we with this set up don't want as much roll, we boost the ARBs considerably to provide a "flat ride" this will let you run with less camber putting more of the tyre on the track at any time generating extra grip. To compensate for the reduced camber however we need to boost the caster angle to aid turn in and exit grip.

The stiffer set up creates a less compliant car that is also much less predictable. Just as fast in the right hands but much harder to score consistently quick laps with.

Rabbit I hate to keep hounding this issue, but the numbers still don't work out bud. A LaFerrari with a weight of 3005lbs, frequency of 4 and a travel of 1.35. You do the math, I've done it over and over and you still get a spring rate that is not available. 4 x 9.86 x 16 x 18.46 x 1.82 = 2120.1. Even after taking the percentage into consideration for weight distribution, it still doesn't work. 2102.1 = F - 1971.6 and R - 2268.5! If you hit me up on party chat, I can walk you through all of this a lot better. I believe you might be on to something with your calculations, but they need some tinkering in order to work. GT = aka Rand0m Her0

Why are we dividing total weight by 2?

You got something wrong there buddy.

3005lbs in KG 1363/4=340.7

4xPI squaredx4xsquareroot340.7x1.35squared=5312.186
That figure becomes 531.22 giving you your Spring rate.

I did say in the top post to divide the final figure by 10.

I also see where you went wrong. You used the old formula. Don't square the frequency and it'll work right

Should look like this
4x9.86x4x18.46x1.82=5300.....
Not quite as accurate as using the formulae on the V3 calculator app (hand writing recognition) saves the brain but it's close enough.

Edited by user Tuesday, October 27, 2015 12:41:47 PM(UTC)  | Reason: Not specified

If you don't understand About500Rabbits read this: http://www.optimumg.com/...nical/technical-papers/

The 6 part Springs and Dampers will explain better.

Just another person wishing Forza operated like real life. I'm guilty of it too, because the tuning can be so fun to try and master.

Yeah trying to convert the formulae using the info we can get hold of has proven to be a complete pig. I got it Sussed in the end though.

I did look at trying to convert the damping and ARB formula but The information needed for those isn't given anywhere at all in game so have nothing to go on so instead applied the principle.

Ok Rabbits, I did not see that you changed it from Frequency Squared to just frequency. Back to testing!! Will let you know how it worked out.

Sorry I am a bit late to the party, thanks for posting this info, but I have something to point out:

In real world calculations, Suspension travel rate in the ratio of how much the wheel moves and how much the spring compresses. It is not overall travel of your wheel. With a real car, you can look up this rate, or measure it, in Forza, we have no idea if they keep this ratio close to the actual cars on stock, and how or if that changes based on modifications.

So based on the math you have been doing, you are still getting good numbers, however your actual frequency is most likely incorrect. Still if it feels good, use it.